White balanced image of surface exposed by skycrane engine blasts, Credit: NASA/JPL-Caltech/MSSS
When landing with the use of rockets it stands to reason that you blow part of the surface covering up. Especially on a dusty planet like Mars. It will surprise nobody that this is exactly what happened. The MastCam 34 of Curiosity imaged her surroundings in high-resolution color images. The above image is part of the mosaic of images, 1,200 by 1,200 pixels each, that resulted from the MastCam imaging for over one hour on August 8, 2012.
Incidentally this view including the coloring is what your own cell phone would record. Because the Mastcam takes color pictures in the exact same manner that consumer cameras acquire color images. In the above version, the colors portrayed are unmodified from those returned by the camera.
The above color image shows an area excavated by the blast of the descent stage Aerojet rocket engines. These 8 thrusters kept Curiosity afloat while hanging on the Sky crane cables, allowing her to be gently let down on the planet. The speed with which she hit the ground was 2.7 kilometers per hour (0.75 meters per second), well within the limits of what she was built to withstand. Just like the rocket engines of the Phoenix lander, when she descended on the North Polar region of Mars 0n May 25, 2007 Curiosity exposed the surface underneath the loose soil. In the case of Phoenix that was permafrost, in this case larger rocks that were not so easily lifted away by the rocket exhausts.
The permafrost that was exposed by the descent thrusters on Phoenix
With the loose debris blasted away by the rockets, details of the underlying materials are clearly seen. What is notable is a rock embedded in a lot of finer material.
The zoom image (white balanced) shows pebbles as large as 3 centimeters (1.25 inches) across (upper two arrows) and a larger clast of 11.5 centimeters (about 4 inches) sticking up for 5 centimeters by (about 2 inches) from the layer in which it is embedded. Clast-rich sedimentary layers can form in a number of ways. Their mechanisms of formation can be distinguished by the size, shape, surface textures and positioning with respect to each other of the fragments in the layers.
This second version, directly below (and the enlarged inset above), shows the colors modified as if the scene were transported to Earth and illuminated by terrestrial sunlight. This processing is called “white balancing” and it transforms the images to colors that would be seen by our eyes on Earth. As you can imagine geologists recognise rocks by their coloring. Therefore transforming the Mars images to ‘Earth’ coloring helps the scientist to recognize and distinguish rocks by color in more familiar lighting.